How many votes did kennedy win when coaklely won 2139 votes?
CREATE TABLE "by_county" (
  "county" text,
  "coakley_pct" text,
  "coakley_votes" real,
  "brown_pct" text,
  "brown_votes" real,
  "kennedy_pct" text,
  "kennedy_votes" real
);
SELECT COUNT("kennedy_votes") FROM "by_county" WHERE "coakley_votes"=2139;