Who was the democratic candidate when the republican was  frank wolf?
CREATE TABLE "match_up_summary" (
  "district" real,
  "incumbent" text,
  "2008_status" text,
  "democratic" text,
  "republican" text,
  "independent_green" text,
  "libertarian" text,
  "other_party" text
);
SELECT "democratic" FROM "match_up_summary" WHERE "republican"='Frank Wolf';