Voters will head to the polls Tuesday in Wisconsin to cast ballots for a number of candidates, but with no top-tier races on the ballot, election officials are expecting low voter turnout.

Democrats will learn who their nominee will be for November's general election against incumbent Republican Gov. Scott Walker. Mary Burke, a former executive of Trek Bicycle Corporation, is up against State Rep. Brett Hulsey.

Another race worth watching is the three-way battle to replace retiring U.S. Rep. Tom Petri, a Republican.