CREATE TABLE student (stuid NUMBER, lname CLOB, fname CLOB, age NUMBER, sex CLOB, major NUMBER, advisor NUMBER, city_code CLOB)
CREATE TABLE voting_record (stuid NUMBER, registration_date CLOB, election_cycle CLOB, president_vote NUMBER, vice_president_vote NUMBER, secretary_vote NUMBER, treasurer_vote NUMBER, class_president_vote NUMBER, class_senator_vote NUMBER)

Find 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" "T1" JOIN "voting_record" "T2" ON "T1"."stuid" = "T2"."class_president_vote"