ROME — Hillary Clinton is holding a steady 13-point lead over Sen. Bernie Sanders among New York Democrats just one week before the primary — thanks to a huge advantage among African-American voters, according to a new poll released Tuesday.

On the Republican side, Donald Trump still holds a massive 35-point lead over Ohio Gov. John Kasich and 36 points over Sen. Ted Cruz, the Quinnipiac University survey found.

Far more Democrats (22 percent) are still undecided about which candidate to support compared to Republicans (6 percent), according to the poll.

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The overall numbers in both the Republican and Democratic races are largely unchanged from Quinnipiac’s poll two weeks ago. A demographic breakdown among Democrats, however, shows Clinton with a significant lead in one category: African-American voters, who favor her 65 percent to 28 percent.

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“Black votes matter for Secretary Clinton in the New York Democratic primary,” Quinnipiac pollster Maurice Carroll said in a statement accompanying the results. White voters are closely divided, with 50 percent favoring Clinton, 45 percent Sanders.

Sanders leads among the 18- to 44-year-old group, 55 percent to 36; Clinton leads among those 45 and older, 62-33. Clinton leads among women, 55-38.

Trump leads his rivals in every breakdown. That includes self-described evangelical Christians, Quinnipiac said. Despite leaning on evangelical activists for support in New York, Cruz trails Trump 41-37 in that demographic breakdown, the survey found.