Different logo on a static subpage

I want a different logo on a special subpage of my homepage. Same I did with the background image of the body. This was easy, because I just changed the style.css by inserting the following code referencing to the specific subpage:

body.singular-page-210 {
background: url(images/example.png);
background-size:100%;
}

But where do I change the logo in the header area left? It is not hardcoded, so I guess I have to change the functions.php? And if so, which function is responsible for inserting the logo?