Tor - The Onion Router

Most sites i see on tor are http://blahblahblah.onion even for sites that have logins such as dread or pitch. However, duckduckgo appears to have an https onion which i didnt think was possible. Now the question is if i submit my user/pass on an http onion is it actually safe and is my session with that site properly secure? I know in transport to me it is secure, but if the exit node knows i want the pitch onion is my account info safe from that node since pitch is http.