CREATE TABLE table_16075179_6 (date_of_appointment VARCHAR2, outgoing_manager VARCHAR2)

When was the date of appointment for the manager replacing Wim Jansen?
SELECT date_of_appointment FROM table_16075179_6 WHERE outgoing_manager = "Wim Jansen"
SELECT "date_of_appointment" FROM "table_16075179_6" WHERE "Wim Jansen" = "outgoing_manager"