When 19th is the position what is the highest amount of poles?
CREATE TABLE "summary" (
  "year" real,
  "class" text,
  "team_name" text,
  "bike" text,
  "riders" text,
  "races" text,
  "wins" real,
  "podiums" real,
  "poles" real,
  "f_laps" real,
  "points" real,
  "pos" text
);
SELECT MAX("poles") FROM "summary" WHERE "pos"='19th';