Tyler Melville added 15 points for the Big Green (6-13, 2-3), as the trio made 20 of 31 field goals. Mitola was 4 of 5 and Melville 3 of 4 from 3-point range.
Dartmouth finished 7 of 15 from 3-point range to 3 of 20 for the Lions (9-10, 1-4).
A 14-2 Columbia run erased an 11-point Dartmouth second-half lead. John Daniels' dunk with 2:41 remaining put the Lions ahead for the last time, 54-52.
Mitola responded with a free throw, a layup and a 3-pointer for Dartmouth.
Mississippi State freshman guard Malik Newman will withdraw from the NBA draft, but sources told ESPN he might explore other opportunities besides returning to Mississippi State.
Seton Hall sophomore Isaiah Whitehead will stay in the NBA draft and not return for his junior season.
Washington State's trio of Josh Hawkinson, Conor Clifford and Ike Iroegbu have withdrawn from the NBA draft and will play their senior season with the Cougars.