What is every original air date for series# of 26?
CREATE TABLE "table1_26866205_1" (
  "series_num" real,
  "episode_num" real,
  "title" text,
  "director" text,
  "writer" text,
  "original_airdate" text
);
SELECT "original_airdate" FROM "table1_26866205_1" WHERE "series_num"=26;