The documentation is clear about this:
OnJoinedRoom:
/// Called when entering a room (by creating or joining it). Called on all clients (including the Master Client).
/// This method is commonly used to instantiate player characters.
/// ...
OnCreatedRoom:
/// Called when this client created a room and entered it. OnJoinedRoom() will be called as well.
/// This callback is only called on the client which created a room (see PhotonNetwork.CreateRoom).
/// ...