Question: What was the GTP winning team in the round in Portland during which Jack Baldwin become part of the GTU winning team?
Schema: create table table_13643320_2 (gtp_winning_team varchar, circuit varchar, gtu_winning_team varchar, PRIMARY KEY (gtp_winning_team))
SQL: select gtp_winning_team from table_13643320_2 where circuit = "portland" and gtu_winning_team = "jack baldwin"