is this a bug or I am blind?

online=# select * from common_logins where username = 'potyty';
 uid | username | password | lastlogin | status | usertype | loginnum
-----+----------+----------+-----------+--------+----------+----------
(0 rows)

online=# select * from common_logins where username like 'potyty';
  uid   | username | password |         lastlogin          | status |
usertype | loginnum
--------+----------+----------+----------------------------+--------+----------+----------
 155505 | potyty   | board    | 2004-08-16 17:45:55.723829 | A      |
S        |        1
  60067 | potyty   | board    | 2004-07-07 20:22:17.68699  | A      |
S        |        3
 174041 | potyty   | board    | 2005-02-17 00:00:13.706144 | A      |
S        |        3
(3 rows)

online=# select username, username = 'potyty' from common_logins where
username like 'potyty';
 username | ?column?
----------+----------
 potyty   | t
 potyty   | t
 potyty   | t
(3 rows)


psql 8.0.3, Debian.

       Mage