CREATE TABLE "episodes" (
  "no_in_series" real,
  "no_in_season" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text
);

Question: Who were the writers of episode 20?
SQL: SELECT "written_by" FROM "episodes" WHERE "no_in_season"=20;