LEWISTON – A new mayor will be sworn in Wednesday if there’s a clear winner in Tuesday’s election.

If not, the city will schedule a runoff election on March 27.

The city announced both dates Tuesday as part of the preparations for Tuesday’s special election ballot.

Voters will pick from four candidates at a special Feb. 27 ballot at the Multi-Purpose Center: School Committee member Leah Poulin, city Councilor Normand Rousseau, former police Chief Larry Gilbert and perennial candidate Charles Soule.

The winner will complete Lionel Guay’s term, which expires at the end of 2007. He or she will be up for re-election on November’s ballot, if the winner of the special election chooses to run again.

The City Charter requires the winner of the ballot to get a clear majority, at least 50 percent of the vote. If he/she doesn’t, the top two vote-getters will face each other in the March run-off.

Tuesday’s ballot also includes a referendum on a bond issue to build a new Pettingill School.