How many starts are associated with an oldsmobile engine, 21 finishes and before 2001?
CREATE TABLE "indianapolis_500_results" (
  "year" real,
  "chassis" text,
  "engine" text,
  "start" real,
  "finish" real,
  "team" text
);
SELECT SUM("start") FROM "indianapolis_500_results" WHERE "engine"='oldsmobile' AND "finish"=21 AND "year"<2001;