Who directed the episode "the departed"?
CREATE TABLE "table1_21025437_6" (
  "episode_no" real,
  "series_no" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "viewers_millions" text,
  "original_airdate" text
);
SELECT "directed_by" FROM "table1_21025437_6" WHERE "title"='\"The Departed\"';