Washington CNN  — 

Donald Trump and Hillary Clinton hold strong leads over their rivals in Pennsylvania, according to an NBC/Wall Street Journal/Marist poll released Sunday.

Trump leads the Republican field among likely Republican voters with 45% support compared to Ted Cruz’s 27% and John Kasich’s 24%.

Clinton is beating Sanders 55%-40% among likely Democratic voters.

Trump is doing best among Republican men and those without a college degree but losing with women and college graduates, according to the poll.

Clinton is beating Sanders handily among African-Americans, voters older than 45, women and self-identified Democrats.

The race in Pennsylvania is complicated by the way Democrats and Republicans select their delegates to the conventions – the people who ultimately decide who wins the nomination.

Democrats award their delegates based on the primary results. But Republican delegates are elected directly by voters in Pennsylvania, separate from the candidates themselves – giving an edge to better-organized campaigns.

Super PACs, campaigns and the Republican candidates themselves have flooded Pennsylvania over the last week with an intense focus on supporting their delegates ahead of Tuesday’s primary.

The poll was conducted from April 18-20. For Democrats, the poll surveyed 734 likely Democratic primary voters with a margin of error of plus or minus 3.6 percentage points. For Republicans, the poll surveyed 571 likely Republican primary voters with a margin of error of plus or minus 4.1 percentage points.