A former Boston teacher’s aide has pleaded guilty to the sexual abuse of two special needs students in different schools last year. The Suffolk district attorney’s office said LaShawn Hill, 34, pleaded guilty Tuesday to one count each of indecent assault and battery on a child, lewd and lascivious conduct, and lascivious acts with a child. Prosecutors said Hill inappropriately touched a developmentally disabled boy about 7 years old in a school bathroom in March 2011. Prosecutors said Hill was found in December 2011 in a therapeutic recreation room at a different school with a 14-year-old severely autistic boy. Hill was sentenced to a term of one to three years in prison.