3 Democrats vie for seat held by the late Sen. Donnelly

ARLINGTON, Mass. (AP) - Three Democrats are vying for the state Senate seat left vacant by the death of Kenneth Donnelly.

Cindy Friedman, state Rep. Sean Garballey and Mary Ann Stewart are on Tuesday’s Democratic primary ballot in the 4th Middlesex District, which includes Arlington, Billerica, Burlington, much of Lexington and Woburn (WOO’-bern).

There are no Republicans on the primary ballot, so the Democratic winner is virtually assured of winning the seat in next month’s special election.

A retired firefighter, Donnelly represented the district from 2009 until his death in April from a brain tumor.

Friedman, an Arlington resident, served as Donnelly’s chief of staff.

Garballey has represented Arlington in the House since 2008 and is vice chair of the education committee.

Stewart, a former Lexington School Committee member, currently serves on the state board of education.