Multiplication by 2 in the Rijndael Galois field
I suspect you got the shift wrong.

Anything shifted left by 1 has an lsbit of 0; if you xor in 010101 (which you do in this case, as the initial value had a 1 msbit), well, 010101 has a 1 lsbit, and the xor of the two must have a 1 lsbit; your result had a 0 lsbit.

Perhaps you're doing a left circular shift (moving bit 7 to bit 0), rather than a left shift (which places a 0 into bit 0)