user: Question: On what circuit was the GTU winning team #59 Brumos Porsche - Audi in round 5? 
Columns: ['Rnd', 'Circuit', 'GTO Winning Team', 'GTU Winning Team', 'TO Winning Team', 'TU Winning Team', 'Results']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Virginia', '#57 Corvette', '#59 Brumos Porsche - Audi', '#21 Javelin', '#71 Opel', 'Results']
SQL:

assistant: SELECT "Circuit" FROM "Table" WHERE "Rnd" = 5.0 AND "GTU Winning Team" = '#59 Brumos Porsche - Audi';