when was the episode named "the doctor is in... deep" first broadcast 
CREATE TABLE "season_6_1997_1998" (
  "no_in_series" real,
  "no_in_season" real,
  "title" text,
  "director" text,
  "writer_s" text,
  "original_air_date" text,
  "production_code" text
);
SELECT "original_air_date" FROM "season_6_1997_1998" WHERE "title"='\"The Doctor Is In... Deep\"';