(Showing my work).
The first thing I tried was the obvious:
sage: vectors = [[1,0,1],[1,0,1],[1,1,0]]
sage: A = matrix(GF(2),vectors)
sage: B = A.kernel()
sage: matrix(B)
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
[...]
ValueError: Invalid matrix constructor. Type matrix? for help
which didn't work. So looked at B:
sage: B
Vector space of degree 3 and dimension 1 over Finite Field of size 2
Basis matrix:
[1 1 0]
and saw that it clearly knows about the matrix I think you're looking for. In Sage, functionality often lives inside objects, so if you type help(B) or or type "B." and then tab, you can see the list of internal functions, and I found both .matrix and .basis_matrix. I think either should work here, so:
sage: M = B.basis_matrix()
sage: M
[1 1 0]
sage: type(M)
<type 'sage.matrix.matrix_mod2_dense.Matrix_mod2_dense'>
sage: M.nrows()
1
Is that what you were after?