What is the smallest season with 6 races, 2 wins, and a Series of all-japan gt championship>
CREATE TABLE "career_summary" (
  "season" real,
  "series" text,
  "races" text,
  "wins" text,
  "position" text
);
SELECT MIN("season") FROM "career_summary" WHERE "races"='6' AND "series"='all-japan gt championship' AND "wins"='2';