How much Average has a Team of san lorenzo, and a 1990-1991 smaller than 45?
CREATE TABLE "relegation" (
  "team" text,
  "average" real,
  "points" real,
  "played" real,
  "1988_89" text,
  "1989_90" text,
  "1990_1991" real
);
SELECT COUNT("average") FROM "relegation" WHERE "team"='san lorenzo' AND "1990_1991"<45;