Which is the episode # of the episode titled "The Man Behind the Curtain"?
CREATE TABLE "season_5_2001" (
  "episode_num" text,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_airdate" text
);
SELECT "episode_num" FROM "season_5_2001" WHERE "title"='\"the man behind the curtain\"';