no , downgrading is not the solution, downgrading is only for taking things to normal. after that disable all your plugins and upgrade again. everything will be ok, as there must be some plugin which is conflicting with upgrade
Connect your server via ftp or winscp or going to control panel and then file manager. First download wp-config.php to your site and then delete entire files present there. Then, download a fresh download of a version 4.1.3 from here to your pc. Now upload it completey to your server. finally upload your wp-config.php. Your website will be live again with previous version of wordpress before upgrade.
