CREATE TABLE table_61726 ("Week" FLOAT, "Date" CLOB, "Opponent" CLOB, "Result" CLOB, "Attendance" FLOAT)

Which Week has Attendance of 51,558?
SELECT MIN("Week") FROM table_61726 WHERE "Attendance" = '51,558'
SELECT MIN("Week") FROM "table_61726" WHERE "Attendance" = '51,558'