problem with function

tbl_prova:

prova | prova2
---------------
sma | sma2
sma3 | sma4

Hi,
i'm using this function:

create fct_prova() returns setof tbl_prova as'
select * from tbl_prova;
' language sql;

When i recall this function with:
select fct_prova();
I see only 2 rows with (probably) the oid.

If i select i have this problem: 
select * from fct_prova() ; 
parser: parse error at or near "(" 

How can i see the real text in the cols when i use the function ftc_prova()? (i must specify more argtype? where?).
Tnx a lot.
Smauroz