How many votes did McCain get in the county where Obama got 50.7% of the votes?
CREATE TABLE "by_county" (
  "county" text,
  "obamapct" text,
  "obamanum" real,
  "mc_cainpct" text,
  "mc_cainnum" real,
  "total" real
);
SELECT MAX("mc_cainnum") FROM "by_county" WHERE "obamapct"='50.7%';