What is the Higgins with a Scallon that is 2%?
CREATE TABLE "opinion_polls" (
  "date" text,
  "source" text,
  "polling_agency" text,
  "davis" text,
  "gallagher" text,
  "higgins" text,
  "mc_guinness" text,
  "mitchell" text,
  "norris" text,
  "scallon" text
);
SELECT "higgins" FROM "opinion_polls" WHERE "scallon"='2%';