What is John Marvin Wierenga's occupation?
CREATE TABLE "28_seats" (
  "riding" text,
  "candidate_s_name" text,
  "gender" text,
  "residence" text,
  "occupation" text,
  "votes" real,
  "rank" text
);
SELECT "occupation" FROM "28_seats" WHERE "candidate_s_name"='john marvin wierenga';