In which years are co-stars  mala sinha and amitabh bachchan?
CREATE TABLE "list_of_songs" (
  "song" text,
  "singer" text,
  "co_singers" text,
  "music_director" text,
  "lyricist" text,
  "co_stars" text,
  "movie_album" text,
  "year" text,
  "additional_info" text
);
SELECT "year" FROM "list_of_songs" WHERE "co_stars"='Mala Sinha and Amitabh Bachchan';