SPRINGFIELD, Ill. (AP) — Don Harmon has been elected as the next Illinois Senate president, becoming the first new leader of the Illinois General Assembly’s upper chamber in more than a decade.

Harmon, an Oak Park Democrat who was elected Sunday by a 37-12 margin, will replace Sen. John Cullerton. The 71-year-old Cullerton last year announced his retirement after four decades in the General Assembly, including five terms as Senate president.

Harmon assumes the top leadership post in the Senate at a time when Democrats hold a supermajority in both General Assembly chambers.

The new Senate president needed support from a majority of the chamber’s 59 members. Democrats currently hold 40 seats.