What is the average Finish, when Team is "Buck Baker", and when Start is less than 13?
CREATE TABLE "daytona_500_results" (
  "year" real,
  "manufacturer" text,
  "start" real,
  "finish" real,
  "team" text
);
SELECT AVG("finish") FROM "daytona_500_results" WHERE "team"='buck baker' AND "start"<13;