Kerala set a global precedent in 1957 by becoming the world's first state to democratically elect a communist government. This historic achievement occurred when the Communist Party of India (CPI) won the state assembly elections in March 1957. E. M. S. Namboodiripad led the CPI to form the government as Chief Minister. This event underscored the efficacy of democratic processes in electing a government with a communist ideology, a unique occurrence in India and globally.
Consequently, the correct answer is: Kerala.