#Haskell, 25 bytes 17 bytes

(!!)$concat$map show[1..]

Champernowne's Constant can be 0 or 1 indexed as C10*.01 is still transcendental.

Edit: as per nimis comment you can use the list monad to reduce this to

(!!)$show=<<[1..]

Haskell, 25 bytes 17 bytes

(!!)$concat$map show[1..]

Champernowne's Constant can be 0 or 1 indexed as C10*.01 is still transcendental.

Edit: as per nimis comment you can use the list monad to reduce this to

(!!)$show=<<[1..]

[Haskell], 25 bytes

(!!)$concat$map show[1..]

Champernowne's Constant can be 0 or 1 indexed as C10*.01 is still transcendental.

#Haskell, 25 bytes 17 bytes

(!!)$concat$map show[1..]

Champernowne's Constant can be 0 or 1 indexed as C10*.01 is still transcendental.

Edit: as per nimis comment you can use the list monad to reduce this to

(!!)$show=<<[1..]