How to set a pin high an keep it there?

[ShortBus]

Utter newbie here... I have three different LEDs on a PIC16F688. Here is my code:

symbol  GREEN = PORTA.1
symbol  ORANGE = PORTA.0
symbol  BLUE = PORTA.2

porta = %00000000
trisa = %00000000

main:
high orange
pause 1000
high green
pause 1000
high blue
pause 1000

end

This code obviously lights the LEDs in sequence. However each LED turns off before the next one is set high. How do light one, then two, and then all three? Thanks!