Which team is John Williams a rider for?
CREATE TABLE "1971_isle_of_man_production_500_cc_tt_fi" (
  "rank" real,
  "rider" text,
  "team" text,
  "speed" text,
  "time" text
);
SELECT "team" FROM "1971_isle_of_man_production_500_cc_tt_fi" WHERE "rider"='john williams';