Which Extra points is the highest one that has a Player of herrnstein, and Points smaller than 30?
CREATE TABLE "michigan_89_beloit_0" (
  "player" text,
  "touchdowns" real,
  "extra_points" real,
  "field_goals" real,
  "points" real
);
SELECT MAX("extra_points") FROM "michigan_89_beloit_0" WHERE "player"='herrnstein' AND "points"<30;