Table: race_results_4
Columns: rnd
circuit
gtp_winning_team
gto_winning_team
gtu_winning_team
results

Question: What was the GTP winning team in the round in Portland during which Jack Baldwin become part of the GTU winning team? 
SQL: SELECT "gtp_winning_team" FROM race_results_4 WHERE "circuit" = 'Portland' AND "gtu_winning_team" = 'Jack Baldwin'

Question: What us the number of the round during which #56 Blue Thunder Racing become the GTP winning team and #38 Mandeville Auto Tech became the GTO winning team? 
SQL: SELECT "rnd" FROM race_results_4 WHERE "gtp_winning_team" = '#56 Blue Thunder Racing' AND "gto_winning_team" = '#38 Mandeville Auto Tech'

Question: How many different results came out of the round in which #98 All American Racers became the GTU winning team? 
SQL: SELECT COUNT("results") FROM race_results_4 WHERE "gtu_winning_team" = '#98 All American Racers'

Question: Who was the GTO winner of the round that ended with Chris Cord becoming the GTU winner? 
SQL: SELECT "gto_winning_team" FROM race_results_4 WHERE "gtu_winning_team" = 'Chris Cord'