What is the % for Munger when McCrory has 40% and the lead margin is greater than 3?
CREATE TABLE "opinion_polling_for_the_united_states_gu" (
  "poll_source" text,
  "dates_administered" text,
  "democrat_beverly_perdue" text,
  "republican_pat_mc_crory" text,
  "libertarian_michael_munger" text,
  "lead_margin" real
);
SELECT "libertarian_michael_munger" FROM "opinion_polling_for_the_united_states_gu" WHERE "republican_pat_mc_crory"='40%' AND "lead_margin">3;