SCHEMA:
CREATE TABLE table_name_29 (winner VARCHAR, team VARCHAR, circuit VARCHAR)
USER:
What is Winner, when Team is "R.J.MacArthur Onslow", and when Circuit is "Oran Park Raceway"?

QUERY:
SELECT winner FROM table_name_29 WHERE team = "r.j.macarthur onslow" AND circuit = "oran park raceway"