CREATE TABLE table_204_33 (id DECIMAL, "number" DECIMAL, "name" TEXT, "year built" DECIMAL, "boat builder" TEXT, "current status" TEXT)

which boat builder is the most popular ?
SELECT "boat builder" FROM table_204_33 GROUP BY "boat builder" ORDER BY COUNT(*) DESC LIMIT 1
SELECT "boat builder" FROM "table_204_33" GROUP BY "boat builder" ORDER BY COUNT(*) DESC NULLS LAST LIMIT 1