PDO, I do not know how to do it right?

Question

PHP

$localhost = 'localhost';
$dbname = 'us3456';
$username = 'root';
$password = '';

try {
    $dbh = new PDO('mysql:host='.$localhost.';dbname='.$dbname.'', $username, $password);
    $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e) { echo 'error_connected';}


$dbh->query("SET NAMES utf8");
$dbh->query("SET CHARACTER SET utf8");
$dbh->query("SET character_set_client = utf8");
$dbh->query("SET character_set_connection = utf8");
$dbh->query("SET character_set_results = utf8");

try {
    $result = $pdo->query("SELECT 1 FROM us3456 LIMIT 1");
} catch (Exception $e) {
    $sql = "CREATE TABLE us3456 (
        `id` INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
        `value` int(11) NOT NULL
        )";

    $dbh->query($sql);
}

I need to create a database if it does not exist, how to do it right? It just won't connect to the database right now because of this.