ASCII file with latitude, longitude and data to GeoTiff using Python

I have a .asc file with three columns of data: longitude, latitude and a data value. Each latitude and longitude point represents the location of a centriod of a 1/8 degree unprojected grid. I want to convert this file to a raster (.tif) using gdal in Python. I then want to use projected datasets to subset this large grid. Any thoughts on how to begin here?