What is Karen Handel polling at in the Insideradvantage poll where John Oxendine is at 15%?
CREATE TABLE "republican_primary" (
  "poll_source" text,
  "dates_administered" text,
  "john_oxendine" text,
  "karen_handel" text,
  "nathan_deal" text,
  "eric_johnson" text,
  "ray_mc_berry" text,
  "undecided" text
);
SELECT "karen_handel" FROM "republican_primary" WHERE "poll_source"='insideradvantage' AND "john_oxendine"='15%';