The mode is the most common number of goals scored per match.
On the pie chart, this will be the 'fattest' wedge:
Mode number of goals = 0
The median is the middle value, when the data is in order. The pie charts begin from 0 goals, and the number of goals increases in an anticlockwise direction, so the pie chart shows the data in order.
After 180$^\circ$, the middle value is reached, so the wedge that the 180$^\circ$ line lands in is the median.