How to mysql delete duplicate rows in a table without id?

13.2.2 DELETE Syntax
Order of Deletion
For mysql delete duplicate rows, you could do a
Delete  limit 1

That will only delete 1 row, even if multiple rows matches the condition. This is explained in the official manual:

If the DELETE statement includes an ORDER BY clause, rows are deleted in the order specified by the clause. This is useful primarily in conjunction with LIMIT. For example, the following statement finds rows matching the WHERE clause, sorts them by timestamp_column, and deletes the first (oldest) one:

DELETE FROM somelog WHERE user = 'jcole'
ORDER BY timestamp_column LIMIT 1;