CREATE TABLE table_name_53 (date VARCHAR(255), winning_team VARCHAR(255), circuit VARCHAR(255))
What is the date of the zolder circuit, which had a.z.k./roc-compétition a.z.k./roc-compétition as the winning team?
    
SQL: SELECT date FROM table_name_53 WHERE winning_team = "a.z.k./roc-compétition a.z.k./roc-compétition" AND circuit = "zolder"