You cannot capture miltank in leafgreen only Pokemon colosseum can.
cheating
use a master ball on it
Sadly, You can't catch Oddish in LeafGreen. You can need to trade it from FireRed.
Its not possible to capture any hoenn Pokemon in leafgreen if you want a roserade trade one from ruby, sapphire or emerald to leafgreen.
Only firered can capture qwilfish trade one from firered to leafgreen.
i am very sorry but you cant get him/her on leaf green.
capture zapdos with an ultra ball
You can capture pidgeotto in berry forest on three island.
You can Capture a Ditto in Pokemon Mansion ( Situated in Cinabar Island )Hope i Helped , If i did , Recommend me Please .
If you push all the boulders into the holes you will be able to capture the Pokemon Unown at the tanoby chambers.
First capture a Weedle or Kakuna then train either to level 10.