Levi or Yisroel for Third Aliyah?

Does anyone know the answer to this scenario. Please
See OC 135:7
The Gabai was not aware that there was a Levi in shul and gave the second aliyah to the original Kohen( As per halachah)

QUESTION: WHO GETS THE THIRD ALIYAH?
A Levi or a Yisroel

Abie

Yisroel

Thank you …
As someone replied on Mi Yodea…he "deduced( my word) that it should be a Yisroel as well.

I am wondering why the question was never addressed. Is it that obvious that it should be the Yisroel.
Since the only time a Yisroel would follow a Kohen is if there are no Levi’im in shul? ( And in my case there is…)
What I did see somewhere is that a Kohen is from Shevet Levi - the inference being that it should not be a problem for the Kohen to take Sheni…He is in effect from Shevet Levi. And that is the Halacha.
On the other hand if there is no Kohen , a Yisroel takes all the Aliyas including Rishon.
Why not allow a Levi to take Rishon and Sheni - since Kohanim derive from Shevet Levi?

Abie

Because the takana was that a kohen takes the first aliya. And a levi takes the second aliya when the first went to a kohen.

I think the pshat is is that the value of a Levi only exists when a Kohen is present. A levi’s service to serve the Kohanim and make their work easier in the Mikdash. Without the Kohen, there is no purpose in the Levi’s work.

You can’t call up a Levi after a Levi. But who said a Levi can’t get rishon if there’s no Cohen?

See BY on saif 6

Re levi getting first Aliyah.
It’s a machlokes haposkim

The Rav holds if there is no Cohen it “unravels”
The package, and a Yisroel (preferably the biggest Talmid chochom) should get Rishon.