PHP on a single page/post

I want to add some PHP code to a single individual page. The code is used to display a list of highest rated and most rated posts on my site. How do I use PHP in a post? I’m thinking I would need to use an IF statement in the page.php file, but I’m not exactly sure what the code would be. My page ID is 196. Can someone tell me the code for doing this? or give me a hint?

Thanks.