CREATE TABLE table_74258 ("Year" FLOAT, "Round" FLOAT, "Winner" TEXT, "Hawthorn score" TEXT, "St Kilda score" TEXT, "Attendance" FLOAT, "Venue" TEXT, "Silk-Miller Medallist" TEXT)

What is the attendance when the hawthorn score is 18.15.123?
SELECT "Attendance" FROM table_74258 WHERE "Hawthorn score" = '18.15.123'
SELECT "Attendance" FROM "table_74258" WHERE "Hawthorn score" = '18.15.123'