Site logo if is home and post thumbnail if is single.. facebook and wordpress

I want my wordpress site to show my site logo if is home or a custom page, else if is a single it should show the post thumnnail on facebook.
And with description I have to do it but in php I don’t know what did I do wrong
Here’s the code of description:

<?php
    if(is_home||is_page(array('oktato-videok','cikkek','hol-csajozz','hol-randizz','galeria','treningek')))
    {
        echo "This is the default wordpress descrition";
    }
    else
    {
        echo wp_title();
    }
?>

If you could help on the description I can make the sufficient changes on my own.

Thanks a lot!