SQL question

Hi,
I have the following table below

SQL> select * FRom mytable;

        A B
---------- ----------

         1          2
         3          4
         2          1
         5          6
         4          3

5 rows selected.

and I like to get the following output:

        A B
---------- ----------

         1          2
         3          4
         5          6
        

basically (1,2) is the same as (2,1) and I would just like to display any of those combination just once.

Not sure how I can write a SQL to extract the data. Can someone help.

TIA. Geraldine

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