CREATE TABLE table_2528382_2 (year VARCHAR2, co_stars VARCHAR2)

In which years are co-stars mala sinha and amitabh bachchan?
SELECT year FROM table_2528382_2 WHERE co_stars = "Mala Sinha and Amitabh Bachchan"
SELECT "year" FROM "table_2528382_2" WHERE "Mala Sinha and Amitabh Bachchan" = "co_stars"