What Filter Directly Edits A WordPress *Page* ?

I know how to edit the posts from a blog but I am confused
as to which of the filters allows me to edit the content of a specific page. I need this functionality so I can pull data from a db
once the page is loaded by a logged in user.

Which filter is proven to offer the best result for something like this? The equivalent of ‘the_content’ for the actual *page* instead of a post.

Thanks.