What was the date of the match against Jean-Julien Rojer, on a clay surface?
CREATE TABLE "challenger_and_futures_runner_up_5" (
  "date" text,
  "tournament" text,
  "surface" text,
  "opponent" text,
  "score" text
);
SELECT "date" FROM "challenger_and_futures_runner_up_5" WHERE "surface"='clay' AND "opponent"='jean-julien rojer';