Which venue did the African Championships have after 2006 with a position of 2nd and 3000 m s'chase in notes?
CREATE TABLE "achievements" (
  "year" real,
  "competition" text,
  "venue" text,
  "position" text,
  "notes" text
);
SELECT "venue" FROM "achievements" WHERE "year">2006 AND "notes"='3000 m s''chase' AND "position"='2nd' AND "competition"='african championships';