Thank you all.
@Mikeb1970 the voltage is 12V, so this should be fine because both transistor support higher voltage.
@MarkT - may be stupid question but what are the saturation characteristics for the transistor? Also I'm checking
https://www.sparkfun.com/datasheets/Components/BC546.pdf and
http://media.nkcelectronics.com/datasheet/s8050.pdf
but can not find the turn off time.