What is the average episode number on 19 March 1993 with Jim Sweeney as performer 1?
CREATE TABLE "series_5" (
  "date" text,
  "episode" real,
  "performer_1" text,
  "performer_2" text,
  "performer_3" text,
  "performer_4" text
);
SELECT AVG("episode") FROM "series_5" WHERE "performer_1"='jim sweeney' AND "date"='19 march 1993';