CREATE TABLE table_53106 ("Race" CLOB, "Circuit" CLOB, "Date" CLOB, "Pole position" CLOB, "Fastest lap" CLOB, "Winning driver" CLOB, "Constructor" CLOB, "Tyre" CLOB, "Report" CLOB)

What date was Joakim Bonnier in the pole position?
SELECT "Date" FROM table_53106 WHERE "Pole position" = 'joakim bonnier'
SELECT "Date" FROM "table_53106" WHERE "Pole position" = 'joakim bonnier'