<?php
$username = $_POST['login_name'];
$password = $_POST['login_password'];
include 'mysql_connect.php';
//$sql_username = $dbh->Query("SELECT username from login");
//$sql_password = $dbh->Query("SELECT password from login");
$sql_login = $dbh->Query("SELECT * FROM `login` WHERE username='$username' AND password='$password'");
if($sql_login->fetchColumn() == 1){
    echo "<br />youve done that!";
}