When did the episode title "Duet For One" air?
CREATE TABLE "season_2_1993_1994" (
  "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_2_1993_1994" WHERE "title"='\"Duet for One\"';