Which Score has an Outcome of runner-up, and a Tournament of johannesburg?
CREATE TABLE "singles_30_15_15" (
  "outcome" text,
  "date" text,
  "tournament" text,
  "surface" text,
  "opponent" text,
  "score" text
);
SELECT "score" FROM "singles_30_15_15" WHERE "outcome"='runner-up' AND "tournament"='johannesburg';