What Pokémon anime series did you watch first?

The first anime series I watched was the first season/original series when it first aired in English on TV.

I vaguely remember being little & watching it around the time it first came out. I stopped at some point, but I remember coming back to it for a brief time at the end of Johto & the beginning of Hoenn, & then stopping again, until I came back sometime during Advanced Challenge & watched it continuously until sometime during DP: Battle Dimension I think. I didn't really touch it again until I started watching the Japanese version sometime during the Sun & Moon era. I was more into the games growing up ever since one of my friends introduced me to Pokemon Crystal.

I started on the Indigo League.

The OS in Korean dub.