CREATE TABLE table_20873 ("Year  ( affiliation ) " TEXT, "Wins" FLOAT, "Losses" FLOAT, "Winning Pct." TEXT, "GB  ( Division Standing ) " TEXT, "Manager" TEXT)

Name the most losses for leslie mann
SELECT MAX("Losses") FROM table_20873 WHERE "Manager" = 'Leslie Mann'
SELECT MAX("Losses") FROM "table_20873" WHERE "Manager" = 'Leslie Mann'