Derek Prince, one of the most admired teacher of the Word of God, explained in this video about the possibility of having both the Holy Spirit and another spirit that is not of God in the life of a Christian believer. It’s a bit of a controversial issue if we think that because the Holy Spirit is holy, and therefore, He cannot co-exist with an unclean spirit. Derek Prince quoted to scriptures that somehow describe this situation: First, Deuteronomy 22:9 which says: “You shall not sow your vineyard with different kinds of seed, lest the yield of the seed which you have sown and the fruit of your vineyard be defiled.” And second, Deuteronomy 22:9 which says: ““You shall not wear a garment of different sorts, such as wool and linen mixed together.”
You just said the answer up above. A clean spirit and an unclean spirit cannot coexist.