Postgres behavior - Conditional statements

HI All,

Found strange behavior of postgres between 9.1 and 9.2. Can some one
pointout the reason for the difference in column name of the output between
the versions?

Postgres 9.1

postgres=> create table test (a int, b int);

CREATE TABLE

postgres=> insert into test values (1,1);

INSERT 0 1

postgres=> select case when exists (select 1 from test where a=1) then 0
else (select b from test where a=2) end;

* case *

*------*

0

(1 row)

Postgres 9.2

postgres=> select case when exists (select 1 from test where a=1) then 0
else (select b from test where a=2) end;

* b *

*---*

0

(1 row)

Regards,

Kumar.