get Collection oder by and limit In Magento

hear  mydesign: is custom module
$limit=10
 $start=0
$modelColl=Mage::getModel('mydesign/mydesign')->getCollection()->addFieldToFilter('user_id',$userId);
            $modelColl->setOrder('mydesign_id','DESC');
            $modelColl->getSelect()->limit($limit,$start);