Name the least rank subcontinent for bangladesh
CREATE TABLE "table1_2248784_3" (
  "rank_subcontinent" real,
  "rank_asia" real,
  "rank_world" real,
  "country" text,
  "2011_gdp_ppp_billions_of_usd" text
);
SELECT MIN("rank_subcontinent") FROM "table1_2248784_3" WHERE "country"='Bangladesh';