Loss of wilcox, and a Date of jun 18 had what opponent?
CREATE TABLE "regular_season" (
  "date" text,
  "opponent" text,
  "score" text,
  "loss" text,
  "crowd" text,
  "record" text
);
SELECT "opponent" FROM "regular_season" WHERE "loss"='wilcox' AND "date"='jun 18';