What is the total number of opponents for the game recorded as 1-3?
CREATE TABLE "schedule" (
  "game" real,
  "date" text,
  "opponent" text,
  "result" text,
  "falcons_points" real,
  "opponents" real,
  "record" text,
  "attendance" real
);
SELECT COUNT("opponent") FROM "schedule" WHERE "record"='1-3';