You mean both LEDs are illuminating together?
The possible reasons are:
1> Your astable is running at higher frequency and you are viewing both at a time (persistence of vision)
But since you are using 10uF, 100k, 10k , it should give a frequency of 'about' 1 Hz aprox. and this must be visible as blinking LEDs!!:roll:
Check all the resistors and capacitor values ones again and verify it is the same as above(if those are lower values, it may show both LEDs glowing at a time due to the increased frequency)
[
Also, it is better to connect the 10k resistor from vcc to pin 7 and the 100k from pin 7 to pin 6 to make the duty cycle 'almost' near to 50%... But be careful not to make the variable resistor 0 ... Also, I think there is no need of 10k variable there, just connect a fixed 10k and if needed, use a 100k variable to increase the blinking speed)..]
Still not working? then the next possibility what I feel is:
2> Your 555 may be bad
and the output is open (high o/p resistance)..
2> Or there may be some continuity problem in the breadboard...Check there is a connection even if you inserted the wires in the right position...
Also, I have a doubt that it may happen if the supply voltage is higher, but not sure about that... (this depends on the 555 output impedance )
I think you can confirm it by testing it after removing one LED...