The field of Democrats running for lieutenant governor — it already includes two Western Massachusetts state senators — continues to grow. Salem Mayor Kim Driscoll entered the race Tuesday, becoming the first mayor to announce a campaign.

A second Western Massachusetts state senator is running for lieutenant governor. State Sen. Eric Lesser, a Longmeadow Democrat and Obama White House alumnus, announced Tuesday that he would enter the race that includes state Sen. Adam Hinds, D-Pittsfield.