I possibly misunderstood it, by I think that if I have
some noncommercial or
no-derivates license (such as CC-BY-NC-ND), then I am allowed to upload
that source text to en.Wikisource.
No, you are not allowed to do that. The text under the edit box states
"Please note that all contributions to Wikisource are considered to be
released under the GNU Free Documentation License". CC-BY-NC-ND is not
compatible with the GFDL, and is also not a free license, so wouldn't
be acceptable on any Wikimedia project.
Angela.