Table schema:
CREATE TABLE table_25597136_1 (date_first_lit VARCHAR, focal_plane_in_ft__m_ VARCHAR)

Question: Focal plane in ft (m) is 43ft (13.1m) is the first date lit.
SQL: SELECT date_first_lit FROM table_25597136_1 WHERE focal_plane_in_ft__m_ = "43ft (13.1m)"