Description:
------------
When querying a firebird database with pdo the values returned for the 1st row of the resultset are empty.
If you change your order or delete a entry the 1st row values  still return nothing.

Reproduce code:
---------------
$db = new PDO ("firebird:dbname=localhost:c:/mydb.fdb", 'SYSDBA', 'masterkey');

try{
  $query = 'select * from HandsetsMake;';
  $res = $db->query($query);
  while($row = $res->fetch(PDO::FETCH_NUM)){
    echo 'Result: '.$row[0].'<br />';
  }
  $cms->commit();
}catch (Exception $e){
  echo 'caught exeption: '.$e->getLine().$e->getMessage();
}

Expected result:
----------------
Result:1
Result:2
Result:3
Result:4



Actual result:
--------------
Result:
Result:2
Result:3
Result:4