Final answer:
The round filled-in note with a line on the side pointing up, known as a quarter note, is played for one beat.
Step-by-step explanation:
The note described in the question is a quarter note and it tells a musician to play the pitch for one beat. When a note is round, filled in, and has a stem that can either point up or down, it is typically played for one beat in common time (4/4 time signature).