vs
QUICK ANSWER
"La campaña" is a form of "campaña", a noun which is often translated as "campaign". "La huelga" is a form of "huelga", a noun which is often translated as "strike". Learn more about the difference between "la campaña" and "la huelga" below.
la campaña(
kahm
-
pah
-
nyah
)A feminine noun is almost always used with feminine articles and adjectives (e.g., la mujer bonita, la luna llena).
1. (politics)
a. campaign 
Esta manifestación es parte de una campaña contra la restricción de las armas.This protest is part of a campaign against gun control.
2. (military)
a. campaign 
Hubo muchas bajas durante la campaña que lucharon en las montañas.There were many casualties during the campaign that was fought in the mountains.
3. (geography)
a. countryside 
Su familia tiene una masía en la campaña del Penedés.Her family has a farmhouse in the countryside of Penedes.
a. season 
Ya que es la campaña de durazno, voy a comprar un montón en el mercado.Now that it's peach season, I'm going to buy a ton at the market.
la huelga(
wehl
-
gah
)A feminine noun is almost always used with feminine articles and adjectives (e.g., la mujer bonita, la luna llena).
a. strike 
La huelga de los maestros cerró las escuelas una semana entera.The teacher strike closed down schools for a whole week.