CREATE TABLE table_73009 ("Six at" TEXT, "Number of editions" FLOAT, "First ridden" FLOAT, "Last ridden" FLOAT, "Most wins by" TEXT)

How many editions have a most wins value of Franco Marvulli (4)?
SELECT COUNT("Number of editions") FROM table_73009 WHERE "Most wins by" = 'Franco Marvulli (4)'
SELECT COUNT("Number of editions") FROM "table_73009" WHERE "Most wins by" = 'Franco Marvulli (4)'