HARRISBURG — A new poll shows Allegheny County Executive Dan Onorato slightly leading the race for the Democratic nomination for governor, although half of the likely voters remain undecided.

Six weeks before the May 18 primary, a Quinnipiac University poll released Wednesday shows Onorato backed by 20 percent of likely voters, followed by former congressman Joe Hoeffel with 15 percent, state Auditor General Jack Wagner with 13 percent and state Sen. Anthony Hardy Williams with 5 percent.

Forty-seven percent of the Democratic respondents said they remained undecided. Among those who had picked a candidate, 70 percent said they still might change their minds.

The poll carries a sampling error margin of plus or minus 3.2 percentage points for the Democratic results and plus or minus 4.4 points for the Republicans.