CREATE TABLE table_1174162_1 (date_first_settled_as_a_suburb VARCHAR2, median_age__in_2006_ VARCHAR2)

What is the date settled for 40 years?
SELECT date_first_settled_as_a_suburb FROM table_1174162_1 WHERE median_age__in_2006_ = "40 years"
SELECT "date_first_settled_as_a_suburb" FROM "table_1174162_1" WHERE "40 years" = "median_age__in_2006_"