CREATE TABLE table_13642023_2 (circuit VARCHAR2, rnd VARCHAR2, gtu_winning_team VARCHAR2)

On what circuit was the GTU winning team #59 Brumos Porsche - Audi in round 5?
SELECT circuit FROM table_13642023_2 WHERE rnd = 5 AND gtu_winning_team = "#59 Brumos Porsche - Audi"
SELECT "circuit" FROM "table_13642023_2" WHERE "#59 Brumos Porsche - Audi" = "gtu_winning_team" AND "rnd" = 5