Voters in Harlem, the New York City neighborhood that once reigned as the epicenter of African-American culture, will go to the polls on Tuesday to pick a candidate to replace Rep. Charles Rangel, who is retiring after 46 years in the U.S. Congress.

Nine Democrats are running to select the party's candidate for November's general election. In a district where Democratic voters heavily outnumber Republicans, Tuesday's winner will have a virtual lock on taking Rangel's vacated seat in the House of Representatives.

Rangel, a founding member of the Congressional Black Caucus, is stepping down at a time of sweeping change in Harlem, the heart of the 13th congressional district.

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Gentrification has emerged as a leading issue in the campaign, as a decade-long influx of affluent residents, many of them white, has transformed Harlem's once-blighted blocks of 19th century brownstone town houses.

In recent years, the district has also experienced a steady increase in new Latino residents, mostly Dominican immigrants and Puerto Ricans.

Both changes have muted the distinctive black identity of the area, the home of the Apollo Theater, the Cotton Club and other monuments of African-American culture.

Rangel, 86, won his first congressional election in 1970, and since then Harlem voters have routinely returned him to office every two years, even after his 2010 censure for ethics violations.

Rangel has endorsed Keith Wright, 61, an assemblyman who represents the heart of Harlem in the state capital. Wright also won an endorsement from civil rights leader Al Sharpton, one of the most influential voices in Harlem.

Calling himself a "warrior against gentrification," Wright has benefited from the help of Rangel's well-oiled organization. But that also has opened him to criticism as a political insider.

The historic concentration of power among so few and the attempt to steer the seat toward a Rangel protege show a "vacuum of leadership" in Harlem, said Fredrick Harris, a professor of political science at New York's Columbia University and director of the Center on African-American Politics and Society.

"You have a couple of generations of young African-American leaders who have been at sea, and now the district is transitioning into something else, said Harris. He noted that Dominicans and other Latinos were becoming a central factor in the district and said the white electorate is a potential "swing vote."

A leading challenger is State Senator Adriano Espaillat, a Dominican-American who tried and failed to unseat Rangel in 2012 and 2014. He was endorsed by the liberal New York Daily News.

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Another contender is Adam Clayton Powell IV, a former state assemblyman and the son of Adam Clayton Powell Jr., who held the Harlem district from 1944 until Rangel defeated him in 1970.

The Powell name may still hold cachet with voters. One of Harlem's main boulevards is named after the elder Powell, an honor he shares with Martin Luther King, Frederick Douglass and Malcolm X, three of the most revered figures in black American history.

The New York Times has endorsed Clyde Williams, a business consultant who has ties to President Barack Obama and former President Bill Clinton. The Times calls Williams a "long shot" but better than the "underachieving establishment old-timers he is fighting to undo."

Suzan Johnson-Cook, a former Clinton adviser, is the only woman in the race. Others in the race are State Assemblyman Guillermo Linares; Mike Gallagher, who has had a career in publishing; Sam Sloan, a centrist in a field of mostly progressives; and Yohanny Careres, a Dominican political newcomer.

At just over 10 square miles, the densely populated congressional district is the smallest of the country's 435. Harlem, starting at the northern end of Central Park, dominates the district, which includes other largely black and Hispanic neighborhoods in the northern tip of Manhattan and southern part of the Bronx.

Once an upscale Dutch neighborhood named after the city near Amsterdam, Harlem drew African-Americans during the northward migration of former slaves in the late 19th Century and again between the world wars. It soon became a leading cultural center, home to black political and commercial life, and an incubator for jazz.

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In decades past, affluent New Yorkers avoided venturing too far north or "uptown." But soaring property values have turned Harlem into one of New York's trendiest real estate markets. White people are moving into new condominium developments and converting old brownstones back into single-family homes after they had been split into smaller apartments.

Powell has vowed to become the "first one standing in front of the bulldozer" to stop the construction of luxury buildings unless they include affordable housing, Newsday reported.