CREATE TABLE "list_of_winners" (
  "year" real,
  "date" text,
  "location" text,
  "winner" text,
  "loser" text,
  "weight_class" text
);

Question: How many years were lightweight class on february 28, 2009?
SQL: SELECT COUNT("year") FROM "list_of_winners" WHERE "weight_class"='lightweight' AND "date"='february 28, 2009';