where democratic coalition is eduardo frei ( pdc ) what are all the alliance
CREATE TABLE "senate" (
  "cons" text,
  "democratic_coalition" text,
  "alliance" text,
  "together_we_can_do_more" text,
  "independent_regional_force" text,
  "independents" text
);
SELECT "alliance" FROM "senate" WHERE "democratic_coalition"='Eduardo Frei ( PDC )';