Did Niels Bohr discover the electron?
No. Bohr was the first to apply energy quantization to the atom, and stated that electrons could exist at only certain allowed energy levels.
The existence of the electron had been postulated prior to 1900, but it was the work of Joseph John Thomson from 1897 to 1901 that demonstrated that all atoms contain electrons. How he did this, and how others such as Ernest Rutherford and Bohr contributed to the early models of the atom makes very interesting reading.
Here are a couple of links you could check out: