Clarifications based on comments from @mgorny

* When an attempt is made to create a second session with the same name-version pair, but the first session is
  in `pending`, `processing`, or `complete` state, the second session is *not* created and a 409 is returned.
* There's nothing special about `0.0.0` as a placeholder version, and it really should be `0.0.0a0`.

Author: warsaw

peps/pep-0694.rst

@@ -437,10 +437,10 @@ the following keys:
 Multiple Session Creation Requests
 ++++++++++++++++++++++++++++++++++
 
-If a second session is created for the same name-version pair while a session for that pair is in the
-``pending``, ``processing``, or ``complete`` state, then the server **MUST** respond with a ``409 Conflict``
-and **MUST** include a ``Location`` header that points to the :ref:`session status URL
-<publishing-session-status>`.
+If a second attempt to create a session is requested for the same name-version pair while a session for that
+pair is in the ``pending``, ``processing``, or ``complete`` state, then a new session is *not* created.
+Instead, the server **MUST** respond with a ``409 Conflict`` and **MUST** include a ``Location`` header that
+points to the :ref:`session status URL <publishing-session-status>`.
 
 For sessions in the ``error`` or ``canceled`` state, a new session is created with same ``201 Created``
 response and payload, except that the :ref:`publishing session status URL <publishing-session-status>`,
@@ -1015,7 +1015,8 @@ name (assuming of course that the name doesn't already exist).
 
 To do this, :ref:`create a new publishing session <publishing-session-create>`, then :ref:`publish the session
 <publishing-session-completion>` without uploading any files.  While the ``version`` key is required in the
-JSON body of the create session request, you can simply use the placeholder version number ``"0.0.0"``.
+JSON body of the create session request, you can simply use a placeholder version number such as
+``"0.0.0a0"``.
 
 The user that created the session will become the owner of the new project.