How many rounds did germán sánchez drive in where the chassis was dallara f308?
CREATE TABLE "teams_and_drivers" (
  "team" text,
  "driver" text,
  "class" text,
  "chassis" text,
  "rounds" text
);
SELECT "rounds" FROM "teams_and_drivers" WHERE "chassis"='dallara f308' AND "driver"='germán sánchez';