What is the average episode # with a name of the origin of Donnie (part 1)?
CREATE TABLE "season_4_2001_2002" (
  "episode_num" real,
  "num_in_season" real,
  "episode_name" text,
  "airdate" text,
  "location" text
);
SELECT AVG("episode_num") FROM "season_4_2001_2002" WHERE "episode_name"='the origin of donnie (part 1)';