SQL injection

[falcifer <falcifer2001 () yahoo es>]

I have the next web to evaluate a sql injection method.
but when i try to perform the injection the query looks like this

usuario--> ' or ''='
password-->  sds


select count(*) from login where usuario='\' or \'\'=\'' and clave='sds'

how can i evade de slash???

-----------------------------------------------------------------------------
<form action="secret.php" method="POST" >
        <center>Usuario <input type="text" name="usuario"><br>
        Password <input type="password" name="password"><br><br>
        <input type="submit" value="Log In"></center>
</form>
<?php
        $mysql=mysql_connect('localhost','root','');
        if($mysql)
        {
                $mysql=mysql_select_db('hackdb');
                if($mysql)
                {
                        $query="select count(*) from login where
usuario='$usuario' and
clave='$password'";
echo $query;
                        $result=mysql_query($query);
                        $count=mysql_result($result,0,0);
                        if ($count)
                        {
                                echo 'has conseguido entrar';
                        }
                        else
                        {
                                echo 'atentificacion fallida';
                        }
                }
                else
                {
                        echo 'No se ha podido seleccionar la base de
datos';
                        exit;
                }
        }
        else
        {
                echo 'No se puede conectar a la base de datos';
                exit;
        }
?>
-- 
falcifer <falcifer2001 () yahoo es>