The Roadrunners (7-3) took a 44-26 lead into halftime before the Presidents (1-9) outscored Ramapo by a 36-35 margin in the second half.
Koch, who now has 1,029 career points, made 10-of-19 shots from the floor and canned three triples. Junior guard Brandon Studer (Johnstown, Pa./Conemaugh Valley) was the only other President in double figures with 11.
W&J shot 37 percent (22-of-59) and was plagued by 24 turnovers.
Ramapo was led by Todd Lowber's 20 points and 11 rebounds. The Roadrunners shot 47 percent (28-of-60) and notched a 47-31 edge on the glass.
Washington & Jefferson rounds out its schedule in Arizona tomorrow afternoon as it takes on Elmira (N.Y.) at 3:00 pm EST.