CREATE TABLE table_name_20 (extra_points INT, points VARCHAR, field_goals VARCHAR)

What is the highest amount of extra points someone got when they scored 28 points but had 0 field goals?
SELECT MAX(extra_points) FROM table_name_20 WHERE points = 28 AND field_goals < 0
SELECT MAX("extra_points") FROM "table_name_20" WHERE "field_goals" < 0 AND "points" = 28