Performer 1 of Stephen Frost, and a Performer 2 of Josie Lawrence, and a Date of 15 September 1995 is what performer 3?
CREATE TABLE "series_7" (
  "date" text,
  "episode" real,
  "performer_1" text,
  "performer_2" text,
  "performer_3" text,
  "performer_4" text
);
SELECT "performer_3" FROM "series_7" WHERE "performer_1"='stephen frost' AND "performer_2"='josie lawrence' AND "date"='15 september 1995';