What are the distinct last names of the students who have class president votes?
SELECT DISTINCT T1.LName FROM STUDENT AS T1 JOIN VOTING_RECORD AS T2 ON T1.StuID  =  T2.CLASS_President_VOTE
SELECT DISTINCT T1.LName FROM STUDENT AS T1 JOIN VOTING_RECORD AS T2 ON T1.StuID  =  T2.CLASS_President_VOTE
[{'LName': 'Smith'}, {'LName': 'Andreou'}, {'LName': 'Adams'}]