When was Elaine Powell (g) of the United states picked?
CREATE TABLE "2006_chicago_sky" (
  "pick" real,
  "player" text,
  "nationality" text,
  "new_wnba_team" text,
  "former_wnba_team" text,
  "college_country_team" text
);
SELECT "pick" FROM "2006_chicago_sky" WHERE "nationality"='united states' AND "player"='elaine powell (g)';