What was the average pick of northwestern state college under round 3?
CREATE TABLE "1981_kansas_city_chiefs_season" (
  "round" real,
  "pick" real,
  "name" text,
  "position" text,
  "college" text
);
SELECT AVG("pick") FROM "1981_kansas_city_chiefs_season" WHERE "round"<3 AND "college"='northwestern state';