What's the original airdate of the episode directed by Pete Travis?
CREATE TABLE "table1_12919003_3" (
  "num" real,
  "episode" text,
  "writer" text,
  "director" text,
  "viewers_millions" text,
  "original_airdate" text
);
SELECT "original_airdate" FROM "table1_12919003_3" WHERE "director"='Pete Travis';