CREATE TABLE table_53103 ("Race" TEXT, "Circuit" TEXT, "Date" TEXT, "Pole position" TEXT, "Fastest lap" TEXT, "Winning driver" TEXT, "Constructor" TEXT, "Tyre" TEXT, "Report" TEXT)

What was the constructor when Jack Brabham was the driver at the Monaco Grand Prix?
SELECT "Constructor" FROM table_53103 WHERE "Winning driver" = 'jack brabham' AND "Race" = 'monaco grand prix'
SELECT "Constructor" FROM "table_53103" WHERE "Race" = 'monaco grand prix' AND "Winning driver" = 'jack brabham'