What are the names of the states that have some college students playing in the positions of goalie and mid-field?
select t1.state from college as t1 join tryout as t2 on t1.cname = t2.cname where t2.ppos = 'goalie' intersect select t1.state from college as t1 join tryout as t2 on t1.cname = t2.cname where t2.ppos = 'mid'