What is the average number of draws for Mortlake club when they have less than 0 wins?
CREATE TABLE "1948_ladder" (
  "club" text,
  "wins" real,
  "losses" real,
  "draws" real,
  "against" real
);
SELECT AVG("draws") FROM "1948_ladder" WHERE "club"='mortlake' AND "wins"<0;