Show the distinct leader names of colleges associated with members from country "Canada".
create table college (leader_name varchar, college_id varchar, PRIMARY KEY (leader_name)); create table member (college_id varchar, country varchar, PRIMARY KEY (college_id))
select distinct t1.leader_name from college as t1 join member as t2 on t1.college_id = t2.college_id where t2.country = "canada"