When interplanet janet is the episode title who is the music by?
CREATE TABLE "table1_191105_3" (
  "episode_title" text,
  "subject" text,
  "music_by" text,
  "performed_by" text,
  "first_aired" real
);
SELECT "music_by" FROM "table1_191105_3" WHERE "episode_title"='Interplanet Janet';