Translate to xPDO

$items = $modx->getCollection('Table', array('actief' => 1, 'frontpage' => 1));

//Query the table
$query = $modx->newQuery('Table');
$query->where(array(
    'actief' => 1,
    'setfrontpage' => 1,
));

//Limit the results AFTER your initial where's (offset start, number to return)
$query->limit('0', '3');
 
//Fetch the results as a collection of objects with our custom query attached
$items = $modx->getCollection('Table', $query);

//Query the table
$query = $modx->newQuery('Table')->where(array('actief' => 1, 'setfrontpage' => 1))->limit('0', '3');

//Fetch the results as a collection of objects with our custom query attached
$items = $modx->getCollection('Table', $query);