What is the average number of draws that have a total of 1 and a goal difference of 2:0?
CREATE TABLE "montenegro_versus_other_countries" (
  "wins" real,
  "draws" real,
  "losses" real,
  "goal_difference" text,
  "total" real
);
SELECT AVG("draws") FROM "montenegro_versus_other_countries" WHERE "total"=1 AND "goal_difference"='2:0';