What was the average of the team if they played 31 games from 1990-1991?
CREATE TABLE "relegation" (
  "team" text,
  "average" text,
  "points" real,
  "played" real,
  "1988_89" text,
  "1989_90" text,
  "1990_1991" real
);
SELECT "average" FROM "relegation" WHERE "1990_1991"=31;