Name the region 1 where region 4 for april 2, 2009
CREATE TABLE "table1_171320_3" (
  "dvd_name" text,
  "ep_num" real,
  "region_1" text,
  "region_2_scandinavia" text,
  "region_2_uk" text,
  "region_4" text,
  "special_features" text
);
SELECT "region_1" FROM "table1_171320_3" WHERE "region_4"='April 2, 2009';